WTB: 3.90 R160 rear diff
 

As the title says, I'm in need of a R160 with a 3.90FD in order for me to get started on my swap.

Please let me know if you have or know of anybody who has it.

That doesn't sound right, not if you've got an '06 6MT to install.

I don't think there were any US subarus that came with a 3.90 LSD. Maybe there were some JDM 5MT STis with 'em? Though I think they probably had R180's too.

This is just based off what info i have found. Here what i was going off of:

AWD 5 Speed transmissions USDM

3.454 / 1.947 / 1.366 / 0.972 / 0.738 / 3.900FD - '02-'05 USDM WRX
3.454 / 1.947 / 1.366 / 0.972 / 0.738 / 3.700FD - '06-'07 USDM WRX
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 3.900FD - '08-current USDM WRX
3.454 / 1.947 / 1.366 / 0.972 / 0.738 / 4.444FD - '04-'08 Forester 2.5XT
3.454 / 2.062 / 1.448 / 1.088 / 0.780 / 4.111FD - '04-current Forester non-turbo
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 4.111FD - '05-'06 USDM Legacy 2.5GT
3.166 / 1.882 / 1.296 / 0.972 / 0.738 / 3.900FD - '07-current USDM Legacy 2.5GT


All-Wheel-Drive 6-speed Transmissions

3.636 / 2.375 / 1.761 / 1.346 / 0.971 / 0.756 / 3.900FD
- USDM 2004-2006 Impreza WRX STi
- UK/Europe/NZ Impreza WRX STi
- JDM Legacy 3.0R Spec B

3.636 / 2.375 / 1.761 / 1.346 / 1.061 / 0.842 / 3.900FD
- JDM Impreza WRX Spec C/STi/STi Spec C RA/V-Limted/S202/S203/S204/Spec C RA-R
- AUS Impreza WRX STi

3.636 / 2.235 / 1.521 / 1.137 / 0.971 / 0.756 / 3.900FD
- USDM 2007-current Impreza WRX STi

Yeah, the final drive is 3.90. But the center diff is 1:1.1, so to get that final drive ratio of 3.90, you need a 3.90 front diff and a 3.545 rear diff.

this craps too confusing. hah ok i'll edit the post then.

You better figure out exactly the ratio of the gearbox. If it really is an '06 6MT, and if the TR already has a 3.545 rear-end, you likely don't need to buy anything.

Get thee to NASIOC!

Thanks for the help scott. haha God, how I hate still being a n00b at this crap! I'll update my thread in the tech section with what i find out and what happens

Well, it used to be a lot easier... then in '06 they changed the ratios on everything.

Your best bet is to get the number off the gearbox itself and get one of the gurus at NASIOC to cross-reference it and let you know exactly what you've got. They will probably also know what's already in the back of the TR.

Ironically, I'm starting to think that you may have a 3.90 R160 back there and will end up needing a 3.545, which is exactly the opposite problem everyone normally has, assuming the '06 WRX 5MT switched to a 1:1 center diff the same time the STi switched to the 1:1.1 center. If that's the case though, I've got a spare non-LSD 3.545 R160 in my garage I'll can sell you for like $50. You can swap the LSD carrier into it from your current diff and be up and running w/ a LSD pretty quick without having to search forever for a complete diff.

But I don't know for sure what ratios come on which cars unless we're talking about '02-'05, since those are the only years I have direct experience with.

I PM'd Fuji K on nasioc. He made the whole gear ration thread.. Im hoping he can help me out. I'll let you know if I end up needing that spare you have. I like 06's.. Until it comes the time to fix them, and nobody know's what to do. haha

"The '06 STi tranny would require to run the 3.545 rear diff. This diff can be found on all '02-05 WRX 5spd manual.


Fuji"

Looks like you were right. I need the 3.545

Well, I've got that 3.545 gearset in an R160 in my garage. We can crack open your (what I'm assuming is a 3.90) and take out the LSD carrier and put it in my R160 and you'll have a LSD 3.545 R160. That's exactly the swap I did when I converted my SVX's LSD R160 from 3.545 to 4.44, which is where the left over open 3.545 I've got came from.

Well, I still need a 3.90FD diff since it's an 05 6spd.

I need a rear diff from one of the following:

NOTE: REAR DIFF Final drives are tranny specific
'98-01 5spd Impreza L/Sport wagon 5spd, or 5spd 95-99 Legacy 2.2L models
02-07 5spd 3.90 Impreza TS/RS wagon/outback sport
06-07 Auto WRX 3.90 VLSD

I still need one of the following since I was sold the wrong rear diff..

'98-01 5spd Impreza L/Sport wagon 5spd, or 5spd 95-99 Legacy 2.2L models
02-07 5spd 3.90 Impreza TS/RS wagon/outback sport
06-07 Auto WRX 3.90 VLSD

You should be able to go to airport auto wrecker, or another wrecker, and get a rear diff off an 02-07 RS/TS. Call around. I'd avoid airport unless you absolutely have to go there tho. Apparently they think their parts are made out of gold, and aren't willing to haggle much in my experience

I totally forgot about going there. Thanks rob. Any other Idea where else I go?

www.car-part.com

You can search nation-wide inventory.

I remember googling auto wrecker or something and calling and asking about the years and models I needed. Sounds like scott has a good site too

Do you remember how mad I was when that hoe bag wouldn't work with me on that stupid center console? :lol:

Austin, you go to cali enough to hit up that D & D auto-wrecker. I know nothing about them except for what I have seen on here from Dean and others.

Yep. And they would not sell me an AC bracket, I had to buy the whole AC setup for $80. All I could do was laugh and walk out.

They wanted $125 for the diff. I took it. :)

ya D&D dismantler is awesome i get a LOT of parts from them. :)

also lmk if a front 3.90 is gonna help you out at all .. :)

If I need one.. Do you have a front?

I doubt Alex has a spare 6MT ring and pinion laying around.